This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-329400, filed Oct. 26, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an ink jet recording apparatus in which an ink jet head including a plurality of ink discharge nozzles arranged to cross with respect to a conveyance direction of a recording medium is used to record an image on the recording medium.
2. Description of the Related Art
A known example of an ink jet recording apparatus is an on-demand type ink jet printer. In the ink jet printer, there is a problem that a nozzle is clogged and non-discharge or defective discharge of ink occurs because of adhesion of the ink in the nozzle in an ink jet head and paper dust of a recording medium.
To avoid this and steadily discharge ink, during the starting of the recording apparatus, before and after the recording, or during the recording, the ink jet head is moved to a maintenance station. Moreover, in the maintenance station, the head is maintained by a method of spitting the ink to an ink absorption material, a method of sucking the ink in the nozzle, or a method of wiping the ink on a nozzle tip end.
However, the ink jet recording apparatus is used to perform printing such as industrial printing in which productivity is very important. In this case, when the ink jet head is periodically moved to the maintenance station and subjected to maintenance, a drop of productivity become to be a problem.
On the other hand, as described in Jpn. Pat. Appln. KOKAI Publication No. 9-254375, when the ink jet head requires the maintenance by ink discharge, without moving the ink jet head to the maintenance station, the ink is spitted to a margin trimmed as unnecessary on the recording medium. Thereby, in the publication, the productivity is enhanced.
Moreover, as a generally known method of detecting a defective nozzle, when the non-discharge or defective discharge of the ink occurs, a method comprises: recording a nozzle check pattern on the recording medium or another recordable place in order to check the ink discharge from each nozzle; and reading and detecting the recorded nozzle check pattern.
However, the above-described publication has a constitution in which only the margin to be trimmed on the recording medium is used to perform the ink spit. Therefore, when the margin to be trimmed does not exist on the recording medium, the ink cannot be spitted. In this case, the ink jet head is periodically moved to the maintenance station and a usual maintenance is performed. There is a problem that an efficiency of maintenance drops and the productivity cannot be enhanced.
Particularly, for the ink jet head, with the use of the ink jet head in which a plurality of ink discharge nozzles are arranged to cross with respect to the conveyance direction of the recording medium, of course when the margin to be trimmed does not exist on the recording medium, and even when the margin to be trimmed exists, but when the margin to be trimmed does not exist entirely over a direction crossing at right angles to the conveyance direction of the recording medium, the spit cannot be performed with respect to all the ink discharge nozzles. Even in this case, the ink jet head is periodically moved to the maintenance station and subjected to the maintenance, and there is a problem that the efficiency of maintenance drops and the productivity cannot be enhanced.
Moreover, to record the nozzle check pattern for checking the ink discharge from each nozzle, when the recording medium is used to record the nozzle check pattern, the recording medium is sacrificed and therefore the productivity drops. Moreover, when the nozzle check pattern is recorded on a recordable place other than the recording medium, the ink jet head is moved to the place, and there is still a problem that the efficiency of maintenance drops and the productivity cannot be enhanced.
An object of the present invention is to provide an ink jet recording apparatus which can enhance an efficiency in performing maintenance by spitting or recording of a nozzle check pattern with use of an ink jet head including a plurality of ink discharge nozzles arranged to cross with respect to a conveyance direction of a recording medium.
According to an aspect of the present invention, there is provided an ink jet recording apparatus to perform printing on a recording medium in which two or more unexposed regions subjected to processing such as trimming, pasting and folding after the printing and thereby unexposed exist in a mixed manner, comprising: an ink jet head in which a plurality of ink discharge nozzles are arranged to cross with respect to a conveyance direction of the recording medium; a spit position determining unit which determines a spit position based on size information and unexposed region information of the recording medium; and a spit control unit which controls spit of the ink jet head based on a spit position judgment result of the spit position judgment unit, wherein the unexposed region information defines regions on the recording medium surface which are unexposed or cut away after printing and processing, and the spit position determining unit selects two or more unexposed regions and determines the spit position so that all the ink discharge nozzles perform the spit.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.